To advance the ongoing NIH funded research at UC, Santa Barbara a Zeiss LightSheet Z.1dual side illumination imaging system (LightSheet) for fast, sensitive imaging of live or dynamic 3D samples. The proposed instrument is not simply an improvement (better, faster, more sensitive) to an existing instrument. The LightSheet is a new type of commercial instrument that is uniquely capable of imaging the dynamic events these researchers study using 3D model systems. After exploring upgrades and testing numerous systems, the researchers found that the LightSheet was uniquely capable of supporting their research projects. Some model systems (e.g. Ascidians, Botryllus schlosseri) do not develop outside carefully controlled environments, particularly when they are repeatedly or continuously exposed to doses of high light. The LightSheet microscope technology limits the light dosage and by decoupling the excitation and emission light path. The LightSheet only illuminates the imaging plane and the emitted fluorescence is collected with a separate objective. The temporal and spatial resolution provided by this instrument are a critically need for ongoing research. To enable the best use and long-term maintenance of the instrument the researchers have gathered significant campus technical and financial support. The instrument would enable not only ongoing campus research but also the development of resources with broader impact.